The present invention relates to an optical scanning system of relatively low mass-inertia adapted to direct radiation beams from a fixed or moving source to form an image or spot at a fixed or desired moving position.
Many attempts have been made to provide optical devices which compensate for positional changes. These systems direct the entire assembly which includes the larger mass-inertia of the telescope. This limits the system frequency response due to power limits on the drive systems, stress levels in the structure, vibration modes and component deformation under accelleration. Other systems for image stabilization such as using gyro control to manipulate a pair of liquid lenses are generally cumbersome and complex.
In practical application, servo scanning systems generally receive radiation energy from a device such as an airplane, ship or other moving objects. The system responds to this energy and produces a local indication from which the position of the object may be determined. Through a suitable servo mechanism, a gun, searchlight or other device may be trained on the object at all times. Such systems are also applicable to signalling systems between ships at sea. In this application, the system must compensate for the relative movement of the two vessels.
A further application of these systems is the continuous scanning of a radiation source as the radiation emitted from a projectile or missile. Since the projectile is moving, it is necessary for the optical system to compensate for its changed position and continuously redirect the image of the projectile to a fixed position. Telescopes are ordinarily employed for this purpose and a servo system which senses the changes in position of the projectile controls the optics of the telescope to accommodate for such position change. Most present accurate art telescopes are quite large and cumbersome, weighing on the order of 4,000 pounds, and therefore have an extremely large inertias, somewhere in the order of 600 ft/lbs/sec.sup.2. To control such a telescope, the servo system must be quite large and high powered. This requirement results in a system less sensitive than that often required.